Morphological and physiological aspects of melanophores in primary culture from tadpoles of Xenopus laevis

Seldenrijk, R.; Hup, D. R. W.; Graan, P.N.E. de; Veerdonk, F. C. G. van de

doi:10.1007/bf00234185

Cited by 40 publications

(19 citation statements)

References 23 publications

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“…The tail-darkening reaction was also described for tadpoles of annuran species, Agalychnis dacnicolor, Phyllomedusa trinitatus, Hyla japonica, and Rana pirica (24)(25)(26), and for a urodela, Hynobius retardatus (26). Melanophores cultured from Xenopus tadpoles at stages 50-54 also respond to light by pigment aggregation (27). The action spectrum for the photoresponse of Xenopus melanophores in intact tails was reported to have a peak at 460 nm by Lythgoe and Thompson (28), whereas Moriya et al (26) showed that a maximum response occurred at 500 nm and that the range is close to the absorption spectrum of rhodopsin in visual rod cells.…”

Section: Light Sensitivity Of Amphibian and Reptilian Chromatophoresmentioning

confidence: 80%

Direct Reception of Light by Chromatophores of Lower Vertebrates

Oshima

2001

Pigment Cell Research

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Rapid color changes of lower vertebrates are caused by the motile activities of pigment cells (chromatophores) present in the skin tissue. Chromatophore motility is generally regulated by neural and/or by endocrine systems. However, in some cases, light also induces pigment aggregation or dispersion directly, which suggests the existence of visual pigments in chromatophores. In fact, some opsins, including melanopsin, have been identified. This article reviews light‐sensitive chromatophores of lower vertebrates. Photoreceptive molecules (visual pigments) and signal transduction of light via a GTP‐binding protein (G protein) are also discussed.

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Section: Light Sensitivity Of Amphibian and Reptilian Chromatophoresmentioning

confidence: 80%

Direct Reception of Light by Chromatophores of Lower Vertebrates

Oshima

2001

Pigment Cell Research

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“…Several extraocular tissues in nonmammalian vertebrates have been shown to be directly photosensitive in culture. These include the pineal gland (Deguchi, 1979), the iris (Barr and Alpern, 1963), and dermal melanophores (Seldenrijk et al, 1979). Within the past 5 years, multiple novel opsins have been identified and localized to extraocular sites in nonmammalian vertebrates.…”

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confidence: 99%

A Novel Human Opsin in the Inner Retina

et al. 2000

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Here we report the identification of a novel human opsin, melanopsin, that is expressed in cells of the mammalian inner retina. The human melanopsin gene consists of 10 exons and is mapped to chromosome 10q22. This chromosomal localization and gene structure differs significantly from that of other human opsins that typically have four to seven exons. A survey of 26 anatomical sites indicates that, in humans, melanopsin is expressed only in the eye. In situ hybridization histochemistry shows that melanopsin expression is restricted to cells within the ganglion and amacrine cell layers of the primate and murine retinas. Notably, expression is not observed in retinal photoreceptor cells, the opsin-containing cells of the outer retina that initiate vision. The unique inner retinal localization of melanopsin suggests that it is not involved in image formation but rather may mediate nonvisual photoreceptive tasks, such as the regulation of circadian rhythms and the acute suppression of pineal melatonin. The anatomical distribution of melanopsinpositive retinal cells is similar to the pattern of cells known to project from the retina to the suprachiasmatic nuclei of the hypothalamus, a primary circadian pacemaker.

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“…Seldenrijk et al (8) have reported that 90 % of cultured melanophores of Xenopus tail fin were responsive to a-MSH, whereas the light response was observed in only 40 % of the melanophores. They thought that the isolated cells more readily lost their capacity to adapt to darkness than to respond to a-MSH.…”

Section: Discussionmentioning

confidence: 99%

“…Of light sensitive chromatophores, isolated pigment cells of the sea urchin Centrostephanus longispinus displayed light sensitivity in the same manner as in normal tissue (1,12), and cultured tail fin melanophores of Xenopus laevis were also light sensitive and responded to light in the same way (8). Wakamatsu (10) found that some cultured melanophores of embryonic tissue and of young fishes of Xi phophorus maculatus exhibited a light-dependent aggregation.…”

mentioning

confidence: 99%